The New HiVIS Spectropolarimeter and Spectropolarimetric Calibration of the AEOS Telescope

We designed, built, and calibrated a new spectropolarimeter for the HiVISspectrograph (R 12000-49000) on the AEOS telescope. We also did a polarizationcalibration of the telescope and instrument. We will introduce the design anduse of the spectropolarimeter as well as a new data reduction package we havedeveloped, then discuss the polarization calibration of the spectropolarimeterand the AEOS telescope. We used observations of unpolarized standard stars atmany pointings to measure the telescope induced polarization and compare itwith a Zemax model. The telescope induces polarization of 1-6% with a strongvariation with wavelength and pointing, consistent with the altitude andazimuth variation expected. We then used scattered sunlight as a linearlypolarized source to measure the telescopes spectropolarimetric response tolinearly polarized light. We then made an all-sky map of the telescope'spolarization response to calibrate future spectropolarimetry.Comment: PASP 118, June 200